Combustion methods and apparatus



Aug. 1, 1961 R. M. SHERMAN COMBUSTION METHODS AND APPARATUS 5Sheets-Sheet 1 Filed June 28, 1954 INVENTOR RALLS ro/v M SHERMAN M MArrrs.

Aug. 1, 1961 R. M. SHERMAN COMBUSTION METHODS AND APPARATUS 5Sheets-Sheet 2 Filed June 28, 1954 /N l E N TOR RALLSTO/V M SHERMAN BY 17 040 M W "W Arr'rs Aug. 1, 1961 R. M. SHERMAN 2,994,367

COMBUSTION METHODS AND APPARATUS Filed June 28, 1954 5 SheetsSheet 3 7 123/ In H /64 L. 6 t 259 we /0 H In l |/67 49.9

lNVENTOR RALLS TON M SHERMAN y (7W Wwmar/111% Aug. 1, 1961 R. M. SHERMAN2,994,357

COMBUSTION METHODS AND APPARATUS Filed June 28, 195 5 Sheets-Sheet 4Aug, 1961 R. M. SHERMAN 2,994,367

COMBUSTION METHODS AND APPARATUS Filed June 28, 1954 5 Sheets-Sheet 5lNl/EN TOR RAL LS ro/v MLSHERMAQI i 4rr'rs.

tates Patented Aug. 1, 1961 2,994,367 COMBUSTION METHODS AND APPARATUSRallston M. Sherman, Glastonbury, Conn., assignor to The Silent Glow OilBurner Corporation, Hartford, Conn., a corporation of Connecticut FiledJune 28, 1954, Ser. No. 439,654 13 Claims. (Cl. 1581) My inventionrelates to combustion methods and apparatus. It has, among its objects,projecting a mixture of fuel and combustion air into a chamber in whichit is burned to produce a flame and hot combustion products, and, tosecure better and more complete combustion of the fuel, guiding saidproducts through a looped path which causes them to travel through thepath of said flame for contact therewith for burning the residual fuelvalues of such products. It further comprehends, among other things,burning a secondary fuel by the heat produced by a primary fuel andmixing the products of combustion of the secondary fuel with those ofthe primary fuel and passing the mixture through the path of the flameproduced by the primary fuel for burning the residual fuel values of themixture. A fluid fuel such as gas or oil is preferably employed as theprimary fuel. The secondary fuel may be fluid or solid fuel. Such solidfuel may be, for example, anthracite or bituminous coal, coke, or wastematerial to be disposed of by incineration, in which latter caseincineration, or the same together with production of hot gaseouscombustion products, may constitute the primary purpose of the apparatusand method.

The invention and its above and other objects will however be bestunderstood from the following description when read in the light of theaccompanying draw-- ings, while the scope of the invention will be moreparticularly pointed out in the appended claims.

In the drawings:

FIG. 1 is a section on the line 11 of FIG. 2, with parts in elevation,of a form of apparatus according to the invention;

FIG. 2 is a section on the line 22 of FIG. 1;

FIG. 3 is a fragmentary section on the line 33 of FIG. 2;

FIG. 4 is a section on the line 44 of FIG. 5 showing a modified form ofapparatus according to the invention;

FIGS. 5 and 6 are, respectively, sections on the lines 5-5 and 6-6 ofFIG. 4;

FIG. 7 is an elevation of another modified form of apparatus accordingto the invention;

FIG. 8 is a section on the line 8-8 of FIG. 7, with parts omitted, thissection line for convenience in following the drawings also beingapplied to FIG. 12;

FIG. 9 is a plan of the apparatus, according to FIG. 7, with the coverremoved;

FIGS. 10 and 11 are, respectively, sections on the lines 1010 and 11-11of FIG. 7, these section lines for convenience in following the drawingsalso being applied to FIG. 12;

FIG. 12 is a section on the line 1212 of FIG. 13, with parts inelevation, this section line for convenience in following the drawingsalso being applied to FIGS. 8, 9 and 10; and

FIG. 13 is a section on the line 1313 of FIG. 12, this section line forconvenience in following the drawings also being applied to FIGS. 8, 9and 10.

The apparatus illustrated by FIGS. 1, 2 and 3 comprises a casing 1 linedwith walls built up of the slab 2, bars 3, and slabs 5, 7, 9, 11 and 13to form a box-like combustion chamber 15, the bars 3 internally of thecombustion chamber having inclined bafile surfaces 16 which convergeupwardly toward each other at the upper transverse corners of thecombustion chamber.

Interiorly of the combustion chamber is shown a block 17 which restsupon the bottom wall of the chamber and laterally conforms to the endand side walls thereof. This block is shown as formed with a slot 19which opens on the upper and lower surfaces of the block and is closedat said lower surface by the bottom wall slab 9 of the combustionchamber so that the slot forms a trough-like recess or passage openingupwardly into the body of the combustion chamber. The slot is shown asextending from the extreme left hand end surface of the block as viewedin FIG. 1 to a portion of the block forming a baifle surface 21 and avertical surface 23, both of which surfaces are positioned transverselyof the slot and extend from one side thereof to the other, the bafflesurface as shown extending downwardly to the left as viewed in FIG. 1from adjacent the right hand end of the upper surface of the block to aportion of the block intermediate its length where it intersects thevertical surface 23, the latter extending downwardly to the lowersurface of the block. As shown, the side wall surfaces 25 of the slotconvergingly incline downwardly from the upper surface of the block tothe upper edges of the lower vertical surfaces 27 of the slot.

As further shown, the lower surface of the block is provided with agroove 29 of rectangular transverse cross-section positioned beneath thebaffle surface 21, the side of the groove where it opens on the lowersurface of the block being closed by the bottom wall slab 9 of thecombustion chamber so as to provide a discharge opening which, as shown,communicates with a discharge conduit 31 for conducting the hotcombustion products to the place where they are utilized. The groove 29,if desired, may be of the same horizontal width throughout its extent asthat portion of the slot 19 which lies between the vertical surfaces 27of the slot. As illustrated, however, this groove at its end adjacentthe slot is of substantially such horizontal width, but its oppositeside Walls converge as shown at 33 (FIGS. 1 and 3) as they extend to thevertical side walls 35 of the remaining and narrower portion of thegroove. With the portion of the groove between the vertical side walls35 of narrower width than that portion of the slot which lies betweenthe vertical walls 27, the products of combustion discharge from thegroove at a greater velocity than if the groove were of substantiallythe same width as such portion of the slot, which higher velocity may bedesirable in certain instances of application of the apparatus.

Interiorly of the combustion chamber is shown a baflle member 37positioned above the block 17 and comprising an approximatelyrectangular bar-like part 39 supported at opposite ends by the oppositecombustion chamber side wall slabs 11. This bar-like part presents theconverging, downwardly facing baffle surfaces 43 and the converging,upwardly facing baffle surfaces 45.

The above described parts contained within the casing 1 of the apparatusmay be formed of heat refractory material such as silicon carbide,alumina, and like refractories, in finely divided form mixed with abinder, molded to shape and baked, in the usual manner of formingbricks, slabs, blocks, and the like for furnace construction.

As shown, the vertical wall slab 7 of the combustion chamber of FIGS. 1to 3 is provided with an opening 49 which receives the discharge endportion of a conduit 51 through the open end 53 of which an atomizedoil-air mixture may be projected into the combustion chamber. Asillustrated, this conduit forms the blast tube of a conventional guntype oil burner, this burner comprising a casing 55 containing anelectric motor driven fan for forcing air from the atmosphere throughthe conduit into the combustion chamber, the amount of air beingregulated in the usual manner by adjustable shutters (not shown) on anend of the casing, which shutters control the size of the air intake tothe fan. As in the conventional gun type oil burner, a pump 57 driven bythe same motor as the fan draws oil through a pipe 59 from an oil tank(not shown) and discharges it under pressure into a pipe 61 incommunication with a pipe 63 positioned axially of the conduit 51, thepipe 63 having at its end adjacent the combustion chamber a spray nozzle65 for atomizing the oil. As in the usual gun type oil burner, the pumpis provided with manually adjustable means (not shown) for controllingthe amount of oil supplied the nozzle. Preferably, and as is commonpractice, positioned in the conduit 51 is a circumferential series ofvanes 67 for causing a whirling of the air discharged from the conduitso as thoroughly to mix the air with the atomized oil. The burner, asshown, is provided with an ignition spark electrode or electrodes 69 forigniting the mixture projected into the combustion chamber.

In operation the burning mixture projected by the oil burner gun travelshorizontally through that portion of the trough which is formed by theinclined Walls 25 of the slot 19 in the block 17 toward the inclinedbaffle surface 21, which latter deflects such mixture and the flameupwardly out of the trough into the space between the bar-like part 39and the end wall slab 5 of the combustion chamber. The top wall andadjacent end wall of the combustion chamber aided by the adjacent bafflesurfaces 16 and 45 turn the products of combustion toward the left asviewed in FIG. 1 at the upper portion of the combustion chamber, the topand left hand end walls aided by the adjacent baffle surfaces 16 and 45then turning such products downwardly into the trough where they passinto contact with the flame into the discharge passage formed by thegroove 29 for discharge from the combustion chamber, thus to cause theflame and products of combustion produced by it, considered as a whole,to follow the general path indicated by the arrows in FIG. 1, that is tosay, in a closed loop for causing the products of combustion produced bythe flame again to be acted upon by the flame prior to their dischargefrom the combustion chamber. The bar-like part 39 and its bafflesurfaces 45, and the bafile surfaces 16, may be omitted if desired, buttheir presence insures satisfactory operation under untoward conditions.The downwardly converging, longitudinally extending surfaces 25 of thetrough-like member act to permit ready upward deflection of theexpanding flame when it strikes the inclined baffle surface 21. At thesame time these surfaces 25 act to guide the downwardly travelingcombustion products into the trough and into contact with the flamebeing projected horizontally through the trough. In the trough thesecombustion products play over the burning oil-air mixture and passaround it and, to some extent, pass through the outer tenuous confinesof the flame. Further, the walls of the trough are heated to highincandescence by the flame, the latter and the downcoming combustionproducts contacting such walls as they are guided by them and as suchproducts pass about the flame to the bottom portion of the trough, andsuch contact acts further to promote combustion particularly as suchproducts, as they pass about the flame, are acted upon by both the flameand said walls. The burning mixture forming the flame being of greaterdensity, particularly at its longitudinally extending center portion,than the combustion products descending to the trough, and beingprojected horizontally with considerable velocity, is not materiallydeflected downwardly by such combustion products. The oil and airmixture, particularly the portion thereof adjacent the discharge end ofthe air blast conduit, acts ejector-like, by reason of its highvelocity, materially to augment and enforce the downward flow of thecombustion products to and into the trough. Also this blast of burningmixture, by such ejector action and by its contact with the products ofcombustion as they pass around it, acts to sweep such products over thehot walls of the trough when in contact with such walls. A finger of theprimary flame may be deflected downwardly and pass into the dischargeconduit from the trough, and some of the downwardly traveling combustionproducts may be caught by the burning mixture and recirculated one ormore times through the looped path in the combustion chamber, but insuch case without deleteriously affecting the efliciency of theoperations and in fact acting to insure complete combustion. It will benoted that the air blast supplied the combustion chamber, and thevoluminous amount of combustion products produced therein, create apositive pressure in the combustion chamber which acts to cause a rapiddischarge of such products from said chamber.

In practice, the amount of air supplied by the oil burner is preferably,but not necessarily, so adjusted with relation to the amount of oilsupplied by it as to secure the maximum primary flame temperature, andmaximum degree of combustion of the oil prior to the combustion productsbeing looped back into contact with the primary flame. Under theseconditions a bright orange primary flame, indicating the maximum flametemperature and degree of combustion possible, will be produced, and,when the oil is the so-called No. 2. oil usually used in domestic guntype oil burners, the amount of such air will be that which will supplyto the oil an amount of oxygen which is about 10 to *12 percent inexcess of that stoichiometrically necessary to secure completecombustion of the oil. Adjusting the air in this preferred way it hasbeen found secures best results in respect to securing maximumcompleteness of combustion by looping the combustion products back tothe flame. However the air may be adjusted to secure other colors offlame, in which case the amount of excess oxygen may be anywhere from 6to 15 percent depending on such color and the particular quality of fueloil employed. Depending upon the quality of the oil and air adjustmentthe temperature of the primary flame may be from about 2000 to 30 00 F.,and the temperature of the combustion products discharged from theapparatus from about -0 to 2400 F. Where conditions warrant, secondaryair may be supplied the combustion products, for example, in the wayhereinafter described in connection with FIGS. 4, 5 and 6, for securingmaximum efliciency.

The gaseous products of combustion of the primary flame will consistmostly of nitrogen admixed with much smaller amounts of carbon dioxideand carbon monoxide, and commonly will contain small amounts ofilluminants, hydrogen, ethane and methane, together with the excessoxygen. These gaseous products ordinarily will also contain finelydivided soot forming carbon particles and usually particles of the heavyend fractions of the oil. The carbon monoxide, illuminants, hydrogen,ethane, methane, carbon particles, and said heavy end fractionsconstitute residual fuel values of the oil, and the amount of suchresidual values is a measure of the incompleteness of the combustion ofthe oil. In the usual case of a gun type oil burner operated in theconventional manner this residual fuel value may amount to as much as 25percent of the total fuel value of the oil. On the other hand, theamount of carbon dioxide present indicates the degree of completeness ofcombustion of the oil. It has been found from flue gas analysis thatpassing the flame and products of combustion, considered as a whole, inthe above described looped path results in many cases in increasing thecombustion of the oil 20 or more percent over that which can be securedunder most favorable conditions when using a gun type oil burner in theconventional way, and with a corresponding increase in the temperatureand volume of the combustion products being discharged from theapparatus.

When the combustion products produced by the primary flame are loopedback and brought into contact with that flame in the way above describedthe intense heat of the flame and walls of the trough raises thetemperature of the combustion products sufficiently to cause theresidual oxygen in the downcoming combustion products to burn theresidual fuel values of those products. The products of combustiondischarged from the combustion chamber are substantially free from sootforming particles, and are entirely odorless. In practice, when burningoil with a bright orange flame, commonly the flame deflected upward bythe baffle surface 21 will disappear at a position about midway theheight of the barlike part 39, and through the remainder of the path oftravel of the combustion products no flame indicating burning of thoseproducts will reappear until said products contact the primary flameproduced by the gun burner in the trough and the adjacent walls of thetrough. In the trough at and beneath the primary flame the secondaryflame will reappear and commonly will fill the bottom portion of thetrough between its vertical surfaces 27 and also the discharge passageformed by the groove 29 in the bottom of the block 17.

Instead of the apparatus burning oil, it may burn a fuel gas, which maybe done by disconnecting the pipe 61 from the pipe 63 and connecting tothe latter a pipe leading from a source of fuel gas under pressure,provision being made for regulating the amount of gas so supplied theburner for regulating the amount thereof supplied the combustion chamberby the nozzle 65 and in any of the ways commonly employed in connectionwith gas burners for supplying furnaces with fuel gas. Also, instead ofutilizing a fluid fuel, the burner may utilize a pulverulent solid fuel,for example sawdust or pulverized coal, in such case the pulverulentfuel being projected through and from the blast tube into the troughadmixed with a blast of combustion air to form the flame, burners of thegun type for so projecting a blast of pulverulent solid fuel andcombustion air being well known. In such case the ash resulting from thefuel will fall to and tend to collect in the bottom portion of thetrough beneath the flame, and will be continuously blown from the troughby and with the products of combustion discharging therefrom through thehereinbefore described discharge conduit from the trough.

The apparatus shown by FIGS. 4, 5 and 6 is substantially identical withthat shown by FIGS. 1, 2 and 3, except that provision is made forsupplying secondary fuel and secondary air to the combustion chamber,while the block 17 of FIGS. 1, 2 and 3 is omitted and a metallic partfunctioning in a substantially identical way substituted for it. InFIGS. 4, 5 and 6 the same reference numerals are applied to the partswhich are common to them and FIGS. 1, 2 and 3.

In the apparatus according to FIGS. 4, 5 and 6 a member 71 issubstituted for the block 17 of FIGS. 1 to 3. This member 71, which isformed of heat refractory heat conductive metal such as stainless steel,may be built up of sheet material to form a welded structure having atop wall 73 provided at each of opposite longitudinally extending sideswith upstanding flanges 75 which bear against the inner sides of theside wall slabs 11 of the combustion chamber, and having at one endthereof an upstanding flange 77 which bears against the adjacent endwall slab 5 of the combustion chamber. As further shown, the top wall 73is provided with an opening 79 extending from the edge 81 of said wall,which edge bears against the inner side of the combustion chamber endwall slab 7, to the upper edge of a flat inclined wall 83. Said upperedge of this wall 83 is shown as positioned close to the end wall slab 5of the combustion chamber, the wall 83 extending inwardly and downwardlyof the combustion chamber to a lower edge thereof positionedintermediate the length of the combustion chamber and above its bottom.Also, as shown, from the longitudinally extending horizontal edges ofthe opening 79 extend downwardly inclined walls 85 which at their loweredges terminate in the same horizontal plane as the lower edge of thein-= clined wall 83. From the lower edges of the walls downwardly extendvertical walls 87, and, from the right hand vertical end edge of one ofthese walls 87 as viewed in FIG. 4, a transverse vertical wall 89extends to the corresponding end edge of the opposite wall 87, the upperedge of the wall 89 extending along and being joined to the lower edgeof the inclined wall 83. At their lower edges the walls 8'7 and 89 areconnected by a bottom wall 91 resting on the upper surface of the bottomslab 9 of the combustion chamber. As shown, the left hand edges of thewalls 85, 87 and 91, as viewed in FIG. 4, abut the inner side of thecombustion chamber end wall slab 7. As further shown, the wall 89 isprovided with an opening 93 with which communicates one end of a conduit94 integral with said wall and connected at its opposite end to thedischarge conduit 95 for conducting the combustion products to a placewhere they are utilized, the discharge conduit 95 being fitted into anopening 97 in the combustion chamber end wall slab 5.

In the above described construction according to FIGS. 4, 5 and 6 theinner surface 99 of the inclined wall 83 of the member 71 forms a bafliesurface which acts in identically the same way in respect to the burningmixture of oil and air as the baflle surface 21 of FIGS. 1 and 2, whilethe inner surfaces of the inclined walls 85 of the member and verticalwalls 87 thereof form a trough extending from the left hand end of themember, as viewed in FIG. 4, to the walls 83 and 89. This troughfunctions in identically the same way as the corresponding trough of theapparatus according to FIGS. 1 and 2.

As shown in FIGS. 4 and 5, there is provided a spray or like nozzle 101for injecting into the upper portion of the combustion chamber asecondary fuel supplied the nozzle by a valve controlled pipe 103. Also,as shown, is provided a conduit 105 which opens through the combustionchamber end wall slab 7 into the chamber formed by the member 71 and theportions of the combustion chamber walls which surround it. This conduitis provided for supplying secondary combustion air to the body of thecombustion chamber into which it discharges in an upward directionthrough openings 107 formed in the top wall 73 of the member 71 to miXwith the upwardly traveling products of combustion, thus to provideadditional air for burning the secondary fuel injected into thecombustion chamber from the nozzle 101. This secondary air in its travelfrom the conduit 105 to the openings 107 is preheated by contact withand radiation from the hot walls of the metallic member 71.

The secondary fuel injected into the combustion chamber of FIGS. 4, 5and 6 may be gaseous or liquid fuel. It, for example, may be an oil tooheavy to be satisfactorily burned by use of the usual gun burner. Suchoil may be supplied the nozzle 101, in which case the nozzle will be aspray nozzle, and the secondary combustion air supplied the conduit 105,by a motor driven pump and fan, respectively, identical with those ofthe gun burner hereinbefore described, except that the oil dischargepipe 61 from the pump of such gun burner will be connected to the nozzlesupply pipe 103 of FIG. 4.

The oil discharged from the nozzle 101 will be ignited by the hotproducts of combustion of the primary fuel and will burn by reason ofthe excess amount of primary air, and the secondary air supplied by theconduit 105, the amount of air supplied by this conduit being soregulated that sufficient oxygen will be contained in the products ofcombustion when they are brought into contact with the primary flame toburn the residual fuel values of the primary and secondary fuels in theway hereinbefore explained.

The nozzle 101 and oil supply pipe 103, instead of being positioned tospray the oil generally horizontally into the combustion chamber, may bepositioned as shown at 101A and 103A, respectively, to spray or drip theoil downwardly onto the upper surfaces of the hot bafiie bar 37,

On such surfaces the oil will spread out in a fihn and volatilize toform oil vapors which mix with the combustion products flowing above thebar and burn. The apparatus may be equipped with both the nozzles 101and 101A, in which case they may be used either selectively orsimultaneously by use of the manually operated valves 103B in the pipes1413 and 103A, these valves if desired being also adjusted forregulating the amounts of oil supplied the nozzles.

It will be understood that after the secondary fuel is ignited by theheat of the primary flame such secondary fuel will continue to burn evenif the primary flame is extinguished. Hence, after the combustionchamber and trough are heated by the primary flame to a high temperaturethe primary oil supply and secondary air supply may be interrupted whilecontinuing the supply of primary air and secondary oil. The primary airupon such interruptions will continue to flow in the hereinbeforedescribed looped path, while the products of combustion of the secondaryfuel will continue to travel as before. Contact of these products ofcombustion with the hot walls of the trough, and any recycling of suchproducts through the looped path that may occur, will promote completecombustion of the fuel, and combustion will tend to keep the walls ofthe trough at high temperature. In the event the walls of the troughfall to an undesired low temperature, as may happen when the fuel valueor the amount of secondary fuel is inadequate to maintain the desiredhigh temperature and as would commonly be the case, the supplies ofprimary fuel and secondary air may be reestablished and such fuelignited by the automatic ignition means (not shown) associated with theprimary fuel nozzle 65 or by the secondary flame, and upon the troughagain being heated to the desired temperature the supplies of primaryfuel and secondary air may again be interrupted.

When both fuels are being burned the trough and the products ofcombustion passing through the discharge conduit 94 will be at a highertemperature than if but the primary fuel only were being burned. Thismay be taken A advantage of for automatically interrupting andreestablishing the supply of secondary air and primary fuel in responseto the temperature of the walls of the trough or such conduit. Forexample, a thermocouple schematically indicated at 1% (FIG. 4) may bewelded to the conduit so as to impress on the leads 103A connected tothe thermocouple elements an electric potential which varies with thetemperature of the conduit, the leads extending through a conduit 108Bfrom the thermocouple to suitable control mechanism for effecting suchautomatic operations. To secure best results this control mechanismshould be such as to interrupt the supplies of primary fuel andsecondary air when the temperature of those walls of the trough whichthe downcorning combustion products contact is well within the rangethat will promote combustion of the residual fuel values of thesecondary fuel conatined in such products, and reestablish such supplieswhen and if such temperature drops to the lower limit of such range.This range may be about 1409 to 2400 F. The temperature of thethermocouple if welded to the conduit 94 may be somewhat diflerent fromthat of these walls of the trough, but by flue analysis of thecombustion products discharging from the conduit when secondary fuelonly is burned the control mechanism actuated in response to thetemperature of the thermocouple may be set to secure optimum results inrespect to completeness of combustion of the secondary fuel withoutknowing what such temperature actually is.

As will be obvious, the supply of primary fuel may be interrupted andreestablished by closing and opening, respectively, a stop valve placedin the suction pipe of the oil pump supplying the spray nozzle for theprimary fuel, and the supply of secondary air may be interrupted andreestablished by closing and opening, respectively, a damper in theconduit 105 supplying such secondary air to the combustion chamber. Thisvalve and damper, as will be understood by those skilled in the art, maybe operated by electromagnetic mechanisms, say solenoids, which areenergized for opening the valve and damper and deenergized for closingthem, or vice versa, such mechanisms being controlled by use of electricrelays operated in response to the potential variations impressed by thethermocouple elements on the leads 108A. As such mechanisms and thecontrolling circuits for them are well known they need not be furtherdescribed.

It will be understood that the supply of secondary air need notnecessarily be interrupted when the supply of primary fuel isinterrupted as a high degree of completeness of combustion of thesecondary fuel will still be effected but with some sacrifice in thetemperature of the products of combustion discharging from theapparatus, which sacrifice in some applications need not beobjectionable. However, in such case ordinarily the supply of primaryfuel must be reestablished at more frequent intervals because of thegreater cooling effect of the excess air on the trough and dischargeconduit. Also, in this case of not interrupting the supply of secondaryair, it is possible to so control the supply of primary air as somewhatto diminish the amount thereof forming the air blast upon the supply ofprimary fuel being interrupted, which may obviously be done by use of adamper in the primary air supply connection to the blast tube, whichdamper the control mechanism governed by the thermocouple will partlyclose when the supply of primary fuel is interrupted, such partialclosure of the damper therefore acting to reduce the total amount of airsupplied the combustion chamber and thus acting to keep the combustionproducts discharging from the apparatus at a higher temperature.

FIGS. 7 to 13 show apparatus according to the invention for burning asolid secondary fuel as well as a fluid primary fuel, the apparatusbeing useful when desired as an incinerator for waste products to bedisposed of.

The apparatus illustrated by FIGS. 7 to 13 comprises a base portion 164and a removable upper portion 165. The base portion, as shown, comprisesa closed circular bottom wall 167 from the periphery of which, andwelded thereto at its lower edge, rises a cylindrical wall 163.Interiorly of the base portion is positioned a trough-like member 169having the opposite vertical end walls 171 and 173 and the oppositeinclined lateral walls 175. This trough-like member, as best shown inFIG. 13, is in transverse cross-section substantially V-shaped, the apex177 of which rests upon the bottom wall 167 of the base portion of theapparatus. The upper open top of this troughlike member is shown in FIG.8 as of substantially square cross-section, and communicates with anopening 179 of the same shape and size formed in a horizontal plate 181.The upper peripheral edge of the trough-like member, as best shown inFIGS. 12 and 13, contacts the under side of the plate 181 about theperiphery of the opening 179 therein, and is welded to the plate. At itsouter edge the plate 181 has a down-turned peripheral flange 183 whichis welded to the upper edge portion of the cylindrical outer wall 168 ofthe apparatus. In this way is formed a chamber 185 interiorly of thebase portion and surrounding the trough-like member.

Positioned in the trough-like member is shown an inclined baflle plate187 which extends from the end wall 173 of said member downwardly to aposition intermediate the height and length of the member. Asillustrated, the baffle plate at its opposite longitudinal edges hasdownturned flanges 189 resting upon the inclined walls 175 of thetrough-like member. These flanges 189, as shown in FIG. 12, are providedadjacent their lower ends with notches 191 which receive pins 193fixedly carried by said inclined walls, for assisting in holding thebaffle plate in the position shown by the drawings. Also, as shown, theentire portion of the end wall 173 of the trough-like member below thehorizontal plane 195 (FIGS. 12 and 13) is cut away to form asubstantially triangular opening 197 at the bottom of said end wall.Registering with this triangular opening and welded to the wall 173about the periphery of said opening is a conduit 199 which is ofcross-section like that of the opening and extends through and fits anopening 201 in the wall 168, to the periphery of which last mentionedopening it is also welded.

As shown, the cylindrical wall 168 and the end wall 171 of thetrough-like member 169 are formed with aligned openings 203 and 205respectively, which openings removably receive the end portion of theair blast tube 207 of an oil or gas burner. This burner may be identicalwith that described in connection with the apparatus according to FIGS.1 and 2, except that as shown in FIGS. 10 and 12 the portion of the airblast tube extending through the chamber 185 is provided withperforations 209 for admitting secondary air into said chamber, so as tocause the blast tube to supply secondary air, as well as to discharge asupply of primary air from the free end of the tube into the trough-likemember 169, the fan of the burner being of suflicient capacity tofurnish both supplies of air. As further shown, the plate 181 definingthe top of the chamber 185 is formed with perforations 210' at theopposite sides of said chamber from the blast tube. In the operation ofthe device the air from the perforations 209 is preheated by the heat ofthe walls of the trough-like member, and discharges from the chamberthrough the perforations 210 into the upper portion of the apparatus forproviding secondary air for burning a secondary fuel introduced intosaid upper portion.

As shown, the removable upper portion 165 of the apparatus according toFIGS. 7 to 13 comprises an outer cylindrical wall 211 which is removablytelescoped into the cylindrical wall 168 of the base portion, and, atits lower edge, removably rests on the upper side of the plate 181.concentrically positioned with relation to the wall 211 is a cylindricalwall 213, the space between the two receiving a mass 215 of heatinsulating material. As shown, the wall 213 at its lower edge removablyrests on the upper edge of a cylindrical stiffening flange 214 risingfrom the plate 181 and welded thereto. At the lower portion of the spacebetween the two walls is shown an annular spacing and connecting member217 of channelshaped cross-section which is welded to said walls and onwhich the mass of heat insulating material rests.

At its upper end the wall 213 is shown as provided withan annularperipheral inwardly extending flange 219 on which, and on the top edgeof the wall 211, rests a plate 221 having a downturned annular flange223 resting against the outer side of the wall 211 and welded thereto.

The plate 221, as shown (see FIGS. 9, 12 and 13), is provided with arectangular opening 225. Resting on the plate and welded thereto at itsperiphery is a circumferentially disposed angle-iron 227. Removablycarried by the upstanding flange 229 of this angle-iron is shown a cover231 for the opening 225, the cover having the downturned peripheralflange 233 which fits over said flange 229. This cover when removedprovides access to the combustion chamber formed by the interior space235 of the upper portion of the device and the communicating interiorspace 237 of the trough-like member.

As shown, removably received in the inner space of the upper part of thecombustion chamber is a foraminous basket 239. This basket, as shown, isof rectangular cross-section at its top, and comprises, the angle-irons241 which extend around its top periphery and provide outwardlyprojecting flanges 243 adapted to rest upon the upper surface of theplate 221 for removably supporting the basket when the latter isinserted through the rectangular opening 225 in said plate. As shown, atthe four corners of the basket are downwardly extending angle-irons 245which are welded to the vertical flanges 247 of the angle-irons 241. Attheir lower portions the angle-irons 245 at each end of the basket arebent toward each other to form portions 247 thereof which are joined at249 so as to give the basket in vertical cross-section a pointed bottom.Also, as shown, for reinforcing the frame it is provided, adjacent theportion of the angleirons 245 where bent to form the inclined portions247 thereof, with flat longitudinally and transversely extending sideand end cross-bars 251, while the angle-irons at each end of the frameare connected by an angle-iron 253 extending from the pointed lower endof the frame at one end of the frame to the corresponding pointed end atits opposite end, the cross-bars 251 and angle-iron 253 being welded attheir ends to the angle-irons 245. To the frame thus formed are weldedthe edges of a coarse wire mesh screen 255 for forming the foraminouswalls of the basket. As shown, the basket at each end of its top isprovided with handles 257 or the like for use in inserting and removingthe basket when the cover 231 is removed.

In operation of the apparatus according to FIGS. 7 to 13 the burningoil-air mixture projected into the combustion chamber strikes the baffleplate 187 so that such mixture and the products of combustion aredeflected upward. This upwardly deflected flame and products ofcombustion divide, as indicated by the arrows in FIG. 13, and passupward into the space at either side of the basket at its end above thebaffle plate, the products of combustion in these spaces turningdownward at the opposite ends of said spaces and reuniting in thetroughlike member and traveling downward through the path of the mixtureprojected by the oil burner through the trough-like member and hencebeneath the baflie plate into the discharge conduit 199.

The basket may be charged with secondary fuel such as bituminous coal,anthracite coal, coke and various combustible waste materials, whichform a secondary fuel, the preheated air admitted to the upper portionof the combustion chamber through the perforations 210 providing thesecondary air for combustion of the secondary fuel. Preferably, butwithout limitation thereto, when the coal or coke is employed it is inlarge lumps, say about the size of a mans fist, so as to provide readypassage through and discharge from the mass of coal of flame andproducts of combustion. The products of combustion of the primary flameformed by the gas or oil burner 'are at a sufficiently high temperatureto ignite the contents of the basket. If the basket is not charged allthe way to its top, and when the top level of the charge descends due toconsumption of the contents of the basket, the products of combustion ofthe primary fuel will freely pass through the portion of the basketabove the charge.

It will be observed in the above respects that the apparatus accordingto FIGS. 7 to 13 operates in a way substantially identical with that inwhich the apparatus according to FIGS. 4 and 5 operates, except that thelatter employs two fluid fuels, instead of a fluid fuel and a solidfuel. In both cases the residual fuel values of the products ofcombustion descending to the lower portion of the combustion chamber areburned by reason of contact of such products with the highly heatedwalls of the trough and with the primary flame created by the oil or gasburner.

The apparatus according to FIGS. 7 to 13 is so designed as to adapt itfor use as an incinerator. For example, the basket may be charged withgarbage and other wastes to be disposed of by incineration. It also isvery well suited for use in connection with the operation of commercialchicken ranches and brooders for incinerating dead, diseased, or spoiledchickens and the wastes resulting from dressing chickens for the market.All these substances, being mainly organic, are in the nature of a fuelwhich burns upon the heat of the primary flame suflicien-tly dehydratingsuch substances and thus supplies a large volume of hot combustionproducts which mix with the combustion products of the primary fuelsupplied by the gas or oil burner, the residual fuel values of themixture being burned by reason of contact of that mixture with theprimary flame and high temperature walls of the trough. When theapparatus is employed as an incinerator the gaseous products dischargedare entirely odorless even when the apparatus is initially started up inthe cold condition. Odor producing contents of such products are mostlyhydrocarbon derivatives such as aldehydes, and the high temperature ofthe primary flame which such products contact is effective entirely toconsume such contents and thus eliminate all odor.

The ash from the material charged to the basket, whether the apparatusis used as an incinerator or otherwise, falls from the basket to thebottom of the troughlike member and is blown from the latter and intoand through the conduit 13 9 by the gaseous products of combustiondischarging through the bottom of the trough. The bottom portion of thistrough-like member at levels below that horizontal plane which includesthe lower edge of the baffle plate 187 may be rectangular incrosssection like the corresponding part of the trough shown in FIGS. 4and 5. However, the triangular shape of this bottom portion provides fora large upper surface area of the ash with relation to the volume of ashtending to collect in said portion, and that facilitates the blowing ofthe ash therefrom. The hot gaseous products containing the ash may bedischarged by the conduit into a separator 259 (FIG. 7) for separatingthe ash from them, from which separator the hot gaseous products maydischarge through the discharge conduit 261 thereof and be conducted tothe place where such products are to be utilized or disposed of, whilethe ash separated from the gaseous products may be removed from theseparator through a normally closed door Q63 provided for that purpose.Separators of this character are well known, and as the details of thesame form form no part of the present invention the separator need notbe further described.

When the apparatus according to FIGS. 7 to 13 is used for incineratingmaterials that tend to produce products of com busion that areobjectionably odorous, for exam ple, materials such as garbage, chickenand other animal flesh, animal wastes, and many industrial wastes, theblast of primary fuel and air mixture may be burned continuously or atleast until such odorous products cease to be contained in thecombustion gases descending to the trough. In most cases of incineratingsuch materials only by continuously burning this blast of primary fueland air mixture will the combustion gases discharged from the apparatusbe entirely odorless and initially be so when the apparatus is put inoperation in the cold condition.

On the other hand, when the substances being incinerated are such thatthey form a secondary fuel that gives off non-odorous combustion gasesafter incineration is continued for a while, or when the secondary fuelis a substance such as coal, coke or other material that gives offnon-odorous or substantially non-odorous combustion gases, the apparatusmay be operated in a way hereinbefore described in connection with theapparatus according to FIGS. 4, and 6, namely, by interrupting thesupply of primary fuel while continuing the blast of primary air uponthe trough being heated to a temperature well within such range thatdespite absence of the primary flame the hot walls of the trough willact on the combustion products of the secondary fuel to cause combustionof the residual fuel values of such combustion products, and upon thetemperature of the trough walls falling to the lower limit of suchrange, as it commonly will after a period of continued operation,reestablishing the supply of primary fuel to again heat the trough wallsto within the desired range of temperatures.

This operation of interrupting and reestablishing the supply of primaryfuel may be done automatically in the way hereinbefore described inconnection with the apparatus according to FIGS. 4, 5 and 6, the controlthermocouple 108 in FIG. 12 being welded to the discharge conduit fromthe trough as in FIG. 4. In the particular form of apparatus shown byFIGS. 7 to 13, however, the only operation necessary to be performed bythe mechanism controlled by the thermocouple 108 is that of interruptingand establishing the supply of primary fuel, which may be done forexample by use of a solenoid valve in the suction pipe of the oil pumpsupplying such fuel to the burner nozzle 65 as hereinbefore explained inconnection with the apparatus according to FIGS. 4, 5 and 6. It will beobserved, however, that in the particular form of apparatus according toFIGS 7 to 13 the secondary air will be supplied to the combustionchamber for so long as the primary air is supplied thereto. Should it bedesired to interrupt and reestablish the supply of secondary air to thecombustion chamber when the supply of primary fuel is interrupted andreestablished the same may be done by omitting the perforations 209 inthe blast tube and providing the combustion chamber with the conduit ofFIG. 4, which conduit as hereinbefore explained in connection with FIG.4 leads from an electric motor driven air fan or blower for supplyingthe combustion chamber through said conduit with secondary air. Whensecondary air is so supplied the combustion chamber of FIGS. 12 and 13such supply may be interrupted and reestablished by interrupting andreestablishing, respectively, operation of the electric motor drivingthe air fan supplying such conduit, which, as will be understood bythose skilled in the art, may be readily done automatically by operationof a switch for connecting and disconnecting such motor to and from thepower line 'which energizes it, such switch being opened and closedautomatically by an electromagnetic instrumentality actuated by thecircuit under the control of the thermocouple.

It will be understood, that within the scope of the appended claims,wide deviations may be made from the forms of the invention hereindescribed without departing from the spirit of the invention.

I claim:

1. The method of simultaneously burning primary fuel in a trough-likespace defined by two coextensive walls, and a secondary fuel, whichcomprises projecting a blast of burning mixture of primary fuel withcombustion air along in said trough-like space defined by and betweensaid walls and longitudinally thereof in close proximity thereto so asto be heated thereby to incandescence, laterally deflecting said blastfrom between said walls after it has traveled a distance between saidwalls, and, while the temperature of the products of combustion of thedeflected blast is above the ignition point of the secondary fuel,bringing said products of combustion and the secondary fuel into contactand introducing secondary combustion air into said products ofcombustion, all for burning the secondary fuel and causing the productsof combustion of the secondary fuel to mix with those of the primaryfuel; and burning residual fuel values of such mixed products by guidingsuch products to such space between said walls at one side of theundeflected portion of the blast for causing such mixed products tocontact said walls and said undeflected portion, and discharging suchmixed products from between said walls at the opposite side of saidundeflected portion at a place spaced, in the direction of travel ofsaid undeflected portion, from the entry of said undeflected portioninto the space between said walls for forcing such mixed products soentering the space between said walls 'to flow from the first mentionedside of said undeflected portion to its opposite side in contacttherewith and said walls.

2. The method according to claim 1 in which the 13 primary fuel is afluid fuel and the secondary fuel is presented by a body ofsubstantially solid fuel, the secondary combustion air being introducedinto the products of combustion of the deflected burning mixture ofprimary fuel and combustion air prior to contact of said products ofcombustion with said body.

3. The method of burning a substantially solid fuel, and a fluid fuel ina space defined by two coextensive upwardly extending walls, whichcomprises projecting a blast of burning mixture of fluid fuel withcombustion air in said space between said upwardly extending walls andlongitudinally thereof in close proximity thereto so as to be heatedthereby to incandescence, laterally deflecting said blast upwardly afterit has traveled a distance between said walls, and, while thetemperature of the products of combustion of the deflected blast isabove the ignition point of the solid fuel, bringing said products intocontact with a body of said solid fuel positioned at a level above thatof the undeflected portion of the blast and introducing secondarycombustion air into such products, all for burning the solid fuel andcausing the products of combustion of the solid fuel to mix with thoseof the deflected blast; and burning residual fuel values of such mixedproducts by guiding such products downward into the space between saidwalls at the upper side of the undeflected portion of the blast forcausing such mixed products to contact said walls and said undeflectedportion, and discharging such mixed products from between said walls atthe under side of the level of said undeflected portion at a placespaced, in the direction of travel of said undeflected portion, from theentrance of said undeflected portion into the space between said wallsfor forcing such mixed products so entering said space to flow from theupper to the lower side of said undeflected portion in contact therewithand said walls.

4. Apparatus for burning a substantially solid fuel, said apparatushaving means forming a combustion chamber, means for supporting in aportion of said chamber that is elevated above the bottom level thereofa bod} of such fuel, means in said chamber at a level below saidsolid-fuel-supporting portion forming a passage having a pair ofopposite walls extending longitudinally of said passage, means forprojecting through said passage longitudinally thereof and between saidwalls a blast of burning mixture of fuel and combustion air in proximityto said walls so as to heat them; means comprising a baflle and anopening from such passage communicating with said solid-fuel-supportingportion of said chamber for laterally deflecting said blast from saidpassage into said chamber portion for contact of the products ofcombustion of said blast with said body and further comprising means forintroducing auxiliary air into said chamber portion, whereby to igniteand burn said solid fuel and cause the products of combustion of suchburning to mix with the products of combustion of the deflected blast;means for discharging products of combustion from said passage at alevel adapted to be below the blast to be projected therethrough and ata location spaced at distance adapted to be removed from the entry ofthe blast into the passage in the direction in which the blast isprojected, and means for conducting such mixed products of combustionfrom said solid-fuel-supporting portion of said chamber to said passageat an area thereof adapted to be adjacent the undeflected portion ofsaid blast for causing flow of such mixed products into said passage forcontact with said Walls thereof and for causing part of said products totravel with the blast to said baflie and such part to be recirculatedthrough said portion of said combustion chamber and also to enforce flowof combustion products including said recirculated part of such mixedproducts from the side of said blast nearer said chamber portion to theside more remote thereto in contact with said walls and said blastwhence to be discharged through said discharge means.

5. Apparatus according to claim 4 in which the passage 14 through whichthe blast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage.

6. Apparatus according to claim 4 in which the passage through which theblast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the walls of said passage flaring away from each-other asthey extend upwardly to said open top from adjacent the portion of saidpassage adapted to be occupied by the blast, whereby to spread the blastas it is being deflected from said passage and to contract the mixedproducts when theyenter said passage and flow toward the undeflectedportion of said blast.

7. Apparatus according to claim 4 in which the passage through which theblast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the walls of said passage flaring away from each other asthey extend upwardly to said open top from adjacent the portion of saidpassage adapted to be occupied by the blast, whereby to spread the blastas it is being deflected from said passage and to contact the mixedproducts when they enter said passage and flow toward the undeflectedportion of said blast, the baffle being operatively positioned at thatend of said passage which is adapted to receive the blast and thedischarge means from said passage being so constructed and positioned asto discharge combustion products from the passage in the direction inwhich the blast is projected through the passage.

8. Apparatus according to claim 4 in which the passage through which theblast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the body of solid fuel being supported at a positiondirectly above said open top, the walls of said passage flaring awayfrom each other as they extend upwardly to said open top from adjacentthe portion of said passage adapted to be occupied by the blast, thebaflle being operatively positioned at that end of said passage which isadapted to receive the blast, the passage having a bottom Wall portionextending longitudinally thereof below and adjacent the space adapted tobe occupied by the undeflected portion of the blast, the means fordischarging combustion products from said passage being positionedadjacent said bottom wall portion and being so constructed andpositioned as to discharge such combustion products from said passage inthe direction in which the blast is projected through said passage,whereby ash falling from the solid fuel will enter said passage throughits open top and tend to collect at said bottom wall portion of saidpassage, and whereby the mixed products of combustion which flow fromthe upper side to the lower side of the undeflected portion of the blastand move with that portion of the blast act to sweep such ash from saidbottom Wall portion into said discharge means.

9. Apparatus according to claim 4 in which the passage through which theblast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the body of solid fuel being positioned in a forarninousreceptacle positioned directly above said open top, the walls of saidpassage flaring away from each other as they extend upwardly to saidopen top from adjacent the portion of said passage adapted to beoccupied by the blast, the baffle being operatively positioned at thatend of said passage which is adapted to receive the blast, the passagehaving a bottom wall portion extending longitudinally thereof below andadjacent the space adapted to be occupied by the undeflected portion ofthe blast, the means for discharging combustion products from saidpassage being positioned adjacent said bottom wall portion and being soconstructed and positioned as to discharge such combustion products fromsaid passage in the direction in which the blast is projected throughsaid passage, whereby ash falling from said receptacle will enter saidpassage through its open top and tend to deposit at said bottom wallportion of said passage, and whereby the mixed products of combustionwhich flow from the upper side to the lower side of the undefiectedportion of the blast and move with that portion of the blast act tosweep such ash from said bottom wall portion into said discharge means.

10. Apparatus according to claim 4 in which the passage through whichthe blast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the body of solid fuel being supported at a positiondirectly above said open top, the walls of said passage flaring awayfrom each other as they extend upwardly to said open top from adjacentthe portion of said passage adapted to be occupied by the blast, thebafiie being operatively positioned at that end of said passage which isadapted to receive the blast, the passage having a bottom wall portionextending longitudinally thereof below and adjacent the space adapted tobe occupied by the undeflected portion of the blast, the means fordischarging combustion products from said passage being positionedadjacent said bottom wall portion and being so constructed andpositioned as to discharge such combustion products from said passage inthe direction in which the blast is projected through said passage,whereby ash falling from the solid fuel will enter said passage throughits open top and tend to collect at said bottom wall portion of saidpassage, and whereby the mixed products of combustion which flow fromthe upper side to the lower side of the undeflected portion of the blastand move with that portion of the blast act to sweep such ash from saidbottom wall portion into said discharge means, said bottom wall portionof said passage being substantially V- shaped in transversecross-section for facilitating such sweeping of the ash.

11. Apparatus according to claim 4 in which the passage thro'ugh whichthe blast is projected has an open top, through which top the blast isdeflected for travel through the portion of the combustion chamber inwhich the body of solid fuel is supported and through which top themixed products of combustion of the deflected blast and solid fuel enterthe passage, the body of solid fuel being supported at a positiondirectly above said open top, the walls of said passage flaring awayfrom each other as they extend upwardly to said open top from adjacentthe portion of said passage adapted to be occupied by the blast, thebafiie being operatively positioned at that end of said passage which isadapted to receive the blast, the passage having a bottom wall portionextending longitudinally thereof below and adjacent the space adapted tobe occupied by the undeflected portion of the blast, the means fordischarging combustion products from said passage being positionedadjacent said bottom wall portion and being so constructed andpositioned as to discharge such combustion products from said passage inthe direction in which the blast is projected through said passage,whereby ash falling from the solid fuel will enter said passage throughits open top and tend to collect at said bottom wall portion of saidpassage, and whereby the mixed products of combustion which flow fromthe upper side to the lower side of the undeflected portion of the blastand move with that portion of the blast act to sweep such ash from saidbottom wall portion into said discharge means, said means fordischarging combustion products from said passage also being positionedadjacent the lower edge of the bafile so that a small part of the blastadjacent its under side will miss the battle and be projected into saiddischarge means to act to force ash entering said discharge meansthrough that means.

12. Apparatus of the character described having means forming acombustion chamber comprising as an internal part thereof a chamberbody, heat refractory incandescible wall means presenting wall surfacesin said combustion chamber forming a trough-like passage which openstransversely thereof at a first portion and at a second portion alongone longitudinally extending margin thereof into the body of thecombustion chamber, means for projecting through said passagelongitudinally there of a blast of burning mixture of fuel andcombustion air in close proximity to said wall surfaces so as to heatthem to incandescence; baflle means in said second portion of thepassage for laterally deflecting said blast from said passage into thebody of the combustion chamber through said second transversely openlongitudinal marginal portion of the passage after the blast hastravelled a distance through said passage; said combustion chamberincluding means adapted for presenting in the path of the deflectedblast a secondary fuel, means including the flow opening from thechamber body to said first passage portion for causing products ofcombustion of the deflected blast to flow through said body to and pastsaid means adapted for presenting secondary fuel and back into saidpassage through said first transversely open longitudinal marginalportion of the passage and laterally of the undeflected portion of theblast at the side of said blast portion facing said last-mentioned openpassage portion, whereby to cause products of combustion so reenteringsaid passage to be guided by said walls into contact with saidundeflected blast portion and part of said reentering products to travelwith such blast portion in contact therewith and along and in contactwith said walls to said baffle means whence to cause said part to berecirculated through said body of the combustion chamber; and meansopening from said first passage portion for discharging products ofcombustion including said recirculated part thereof from said passage,said discharging means being generally parallel to and at that side ofthe path of travel of said undeflected portion of the blast which isopposite to said open passage portions and at a location along said pathspaced from the blast projecting means for thereby forcing such productsof combustion to flow from that side of the undeflected portion whichfaces said transversely open passage portions to the opposite side ofsaid undeflected blast portion and over and in contact with said \wallsand in contact with said blast portion and so as to be discharged inparallelism therewith.

13. Apparatus of the character described having means forming acombustion chamber comprising a base chamber portion and an upperchamber portion with top closure, heat-refractory inoandescible wallmeans presenting wall surfaces in said base chamber portion and formingan upwardly flaring trough-like passage which at a first longitudinalportion and at a second longitudinal portion opens upwardly toward andinto the upper chamber portion of the combustion chamber, means forprojecting through said trough-like passage longitudinally thereof ablast of burning mixture of fuel and combustion air in close proximityto said wall surfaces so as to heat them to incandescence; baffle meansin said second portion of the pas- 17 sage for upwardly deflecting saidblast into the upper combustion chamber portion through said secondportion of the passage after the blast has travelled a distance throughsaid passage; said upper chamber portion having at the central regionthereof flow directing and combustion promoting means including upwardlyand outwardly inclined lower wall elements located and arranged belowand relative to the top closure of the upper chamber portion to aflordlateral passage for the deflected blast and combustion products at theupper end of said upper chamber portion so as to traverse the latter andthence to flow downward back toward the first portion of the trough-likepassage in a closed vertical loop past said flow directing means, meansincluding the flow opening between the chamber body and said firstportion of the trough-like passage for causing products of combustion ofthe deflected blast so to flow across and from said upper chamberportion back into said trough-like passage through said open firstportion thereof and laterally of the undeflected portion of the blastwhereby to cause products of combustion so re-entering said passage tobe guided by said wall surfaces into contact with said undeflected blastportion and part of said reentering products to travel with such blastportion in contact therewith and along and in contact with said wallsurfaces to said upwardly deflecting baffle means whence to cause saidpart to be recirculated through said upper combustion chamber portion;and elongate passage means opening from said first longitudinal portionof the trough-like passage for discharging products of combustionincluding said recirculated part thereof from said passage, saiddischarging means being generally parallel to and below the trough-likepassage and at a location therealong spaced from the blast projectingmeans for thereby forcing such products of combustion to flow from theupper to the lower side of the undeflected blast portion in the firstlongitudinal portion of said trough-like passage and over and in contactwith said wall surfaces and in contact with the blast portion in saidfirst passage portion and so as to be subject to ejector discharge atthe base chamber portion below and in general parallelism with saidtrough-like passage.

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